A Geological and Hydro-Geochemical Study of the Animas Geothermal Area, Hidalgo County, New Mexico

Journal Article: A Geological and Hydro-Geochemical Study of the Animas Geothermal Area, Hidalgo County, New Mexico

Abstract

The Animas Valley thermal area lies on the west pediment of the Pyramid Mountains. The Pyramids are composed of Cretaceous to Teritary igneous rocks. Two hot wells produce 101°C water at a depth of 20 meters. The wells seem to relate to a northerly trending fault having at least 500 meters displacement with the west block downthrown. An elliptical heatflow anomaly extending about 3 km in length occurs in this area. Thermal waters contain about 1200 mg/l of dissolved solids and low concentrations of Li, B, NH3 and H2S. Silica concentrations do not exceed 145 mg/l. Cations and anions occur as: SO4.C1.HCO3 Na>Ca>K>Mg. Last equilibrium with a volcanic suite of minerals and carbonates is evidenced. Geothermometers indicate subsurface temperatures of approximately 160°C. Apparently the thermal waters are escaping rapidly from a deep (>4 km) reservoir along a conduit formed by fault intersections. Evidence of igneous heat is lacking.